As most readers know, anxiety disorders and depression account for a huge burden of disease globally. Mental health disorders have been estimated to cost the world approximately $1.15 trillion per year (Chisholm et al. 2016) and healthcare spending continues to grow. Internet-based psychological interventions (IPIs) have been developed in response to barriers to access, workforce shortages, long waiting times, stigma, and the high costs of existing treatments. There has been a growing body of research on the effectiveness of IPIs with multiple meta-analyses suggesting that these interventions can be effective for the treatment of anxiety and/or depression (Karyotaki et al. 2017; Păsărelu et al. 2017). But are they cost-effective?
On the Mental Elf, we have previously examined the cost-effectiveness of at least two IPIs: iCBT for OCD in young people, and Internet-based problem-solving guided self-help for depression. The former blog investigating internet-based CBT (i-CBT) for OCD found the IPI to be both promising and cost-effective, however there were many limitations associated with the study’s methods. The latter article examined the cost-effectiveness of an internet-based problem-solving self-help guide for depression and found it was neither effective nor cost-effective. A mixed picture for IPIs. Since these articles were published, there has been a large growth in studies examining the effectiveness and cost-effectiveness of IPIs.
The focus of this blog post is an article which summarises all this new research on the cost-effectiveness of IPIs. The paper takes the form of a systematic review focussed on the cost-effectiveness of IPIs specifically in anxiety disorders and depression.
The paper has two primary goals:
- To summarise the cost-effectiveness literature examining IPIs in the context of anxiety disorders and depression
- To examine the costing methods used within these studies of IPIs.
This blog post will only deal with the first goal as the intricacies of costing methodology across studies is likely only to appeal to highly enthused health economists.
The paper conducted a systematic review in accordance with PRISMA reporting guidelines. The review was comprehensive; covering all of the main databases that would be expected (MEDLINE, EMBASE and many others). The search strategy was broad, to ensure that all relevant records would be found.
The criteria for inclusion in the review were:
- Interventions for anxiety disorders or depression
- Evaluated the use of an internet delivered intervention
- Recruited participants
- Assessed the costs of an internet intervention
Study selection and data extraction was conducted rigorously (double reviewed and double extracted). The Drummond checklist (Drummond et al. 2005) was used to appraise the quality of the economic evaluations.
Thirty-three unique studies were included in the review. The results are broadly split into IPIs for anxiety disorders, and IPIs for depression.
Internet-based psychological interventions for anxiety disorders
There were 13 studies that assessed the costs of IPIs for anxiety disorders. Twelve of these were RCTs whilst one was a feasibility study. All IPIs were i-CBT and most (N=10) involved regular contact with a therapist or a coach. Comparators included usual care/waitlist, in-person CBT, an alternative IPI and a less intensive IPI.
Intervention costs per participant ranged from $124 to $1,001 per participant (mean $413). Of the seven studies that conducted an economic evaluation using QALYs as outcome, all found the IPIs to be cost-effective with incremental cost-effectiveness ratios (ICERs) ranging from -$19,659 to $10,298 per QALY, with one other study finding that the intervention dominated control (i.e. more effective and cheaper). Of note, the majority (five) of the these were conducted in Sweden with just two being conducted elsewhere.
Internet-based psychological interventions for depression
Twenty studies considered IPIs for depression. Eighteen were RCTs, one study was a feasibility trial, and one was an observational study. Almost all (N=19) were based on CBT and the majority (N=17) were internet-delivered self-help courses whilst two were blended with in-person sessions and one was therapist delivered using instant messaging. Most of the self-help IPIs still required regular contact with a therapist.
Intervention costs ranged from $0 to $2,842 per participant (mean $623). Of the 20 included studies, 16 conducted a cost-effectiveness analysis. The cost-effectiveness results of IPIs for depression were more varied than that of anxiety disorders. ICERs ranged from -$6,929 to $717,530 per QALY. The authors present a mean ICER however this is not informative. Eleven (69%) of the studies concluded the IPIs were cost-effective whilst 5 (31%) concluded they were not.
The primary findings suggest that IPIs have the potential to be cost-effective interventions for use in patients with anxiety disorders or depression. Across both conditions, 81% of the studies that reported cost-effectiveness results concluded that the IPI was more cost-effective than the control condition. When considering anxiety disorders and depression in isolation the results were more favourable for IPIs in anxiety disorders where all the IPIs were found to be cost-effective. The results for depression were less convincing, with 69% of the studies finding the IPI to be cost-effective.
The authors present reasons why the results for depression are less convincing than for anxiety disorders, these include:
- Depression being fundamentally different to anxiety disorders and less responsive to IPIs
- A wider range of heterogeneity in across studies in terms of country, intervention and methods used within the depression research.
Strengths and limitations
Since the previous Mental Elf blogs (published in 2016-17), it is encouraging to see more studies assessing the cost-effectiveness of IPIs. The evidence compiled in this review looks very favourable for the use of IPIs in anxiety disorders and also promising for use with depression. However, we must be cautious in interpreting the results and generalising to all IPIs.
IPIs can come in many forms, the majority of IPIs were CBT based self-help but included regular contact with therapists. These results may not translate into cost-effectiveness for other IPI types. For example, there exist over 10,000 apps for mental health, some of which have shown promise. However, only one app was covered within this review (an app for anxiety disorders), whilst this single study found the app to be cost-effective, we cannot generalise these findings to all apps more generally. Given the prevalence and accessibility of smartphone apps this should be a priority for further research. Additionally, this could offer an easy gateway to support and care for those who are reluctant (e.g., due to stigma) to engage with formal services.
Whilst all the economic evaluations of IPIs in anxiety demonstrated cost-effectiveness, we should again be cautious about generalisability to other contexts. Five of the seven studies were conducted in Sweden and the IPIs may not translate to other countries in terms of cost-effectiveness, especially when considering that criteria for cost-effectiveness (and methods of economic evaluation preferred by local decision makers) may differ across countries.
The relatively small number of studies combined (with heterogeneity across studies) limit the strength of findings, consequently it is not possible to delve deeper and identify specific types of IPIs in specific contexts that are particularly effective and cost-effective.
Whilst the majority of the IPIs for depression were cost-effective, nearly a third were not. Whether this is due to the increased heterogeneity in studies (many countries, different types of IPIs) or due to depression being more resistant to the benefits of IPIs remains to be seen.
Implications for practice
Given the painfully long waitlists and chronic issues with accessibility to mental health care, IPIs appear an ideal stop-gap solution to allow people to get access to immediate care and this article supports that view. This article suggests that there is growing evidence that IPIs are a cost-effective therapeutic treatment for anxiety disorders and depression. There still remains a need for further research, especially regarding the cost-effectiveness of app-based technology that can be quickly and easily accessed with few barriers to entry. Likewise, especially for depression, there needs to be greater attention paid to which types of interventions work best, in what circumstances, and for whom.
There remain some equity concerns surrounding IPIs, there are those that may not have access to the equipment required to use IPIs. For example, recently during COVID-19 we saw that those in deprived areas were more likely to have difficulties with home schooling using internet-based teaching. Similarly, there are those, particularly in older generations, who may not be as familiar with internet-based technology who are unable to benefit from such interventions. For this reason, traditional methods of therapeutic care remain vital, regardless of the efficacy and cost-effectiveness of IPIs in comparison.
Statement of interests
No conflicts of interest to report.
Mitchell L, Joshi U, Patel V, Lu C, Naslund J (2021) Economic Evaluations of Internet-Based Psychological Interventions for Anxiety Disorders and Depression: A Systematic Review. Journal of Affective Disorders, 2021 Vol 284 pp157-182. https://doi.org/10.1016/j.jad.2021.01.092
Canaway A. iCBT for OCD in young people: study suggests it’s cost-effective, but more research needed, The Mental Elf, 4 Aug 2017,
Canaway A. Internet-based problem-solving guided self-help for depression whilst waiting for therapy, The Mental Elf, 2 Aug 2016,
Chisholm D, Sweeny K, Sheehan P, Rasmussen B, Smit F, Cuijpers P, Saxena S (2016) Scaling-up treatment of depression and anxiety: a global return on investment analysis. The Lancet Psychiatry, 3 (5) (2016), pp. 415-424
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Karyotaki E, Riper H, Twisk J, Hoogendoorn A, Kleiboer A, Mira A, Mackinnon A, Meyer B, Botella C, Littlewood E (2017) Efficacy of self-guided internet-based cognitive behavioral therapy in the treatment of depressive symptoms: a meta-analysis of individual participant data, JAMA Psychiatry, 74 (4) (2017), pp. 351-359
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